Salt in a salt formation behaves as a plastic and exhibits creep when subject to differential stresses. If a wellbore is drilled through the salt formation, the in-situ stresses in the region around the wellbore alter. For example, the horizontal in-situ stresses at the location of the wellbore before the wellbore is drilled, are replaced by horizontal stresses of magnitude corresponding to the hydraulic fluid pressure in the wellbore. If this fluid pressure is lower than the far field horizontal in-situ stresses in the salt formation, the salt in the vicinity of the wellbore will creep radially inward thus reducing the cross-sectional size of the borehole. Many times such radial deformation of the wellbore wall will be non-uniform, either in axial direction or in circumferential direction of the borehole. In view thereof, radial deformation of the wellbore wall can be more pronounced at some locations than at other locations so that a casing present in the wellbore can be subjected to locally high radial loading conditions as a result of the salt deformation. Non-uniform loading conditions can also occur if the borehole has an irregular shape due to, for example, washouts during drilling. Such irregularly shaped borehole will initially contact the casing at discrete points thereof due to creep of the salt formation and will thereby potentially cause local damage to the casing, for example by buckling of the casing. If the casing has been cemented in the borehole, the cement would normally fill the irregularities in the borehole and thus compensate for the non-uniform loading condition. However in many instances the cement not will not completely fill the borehole irregularities, especially if large washouts occur in the borehole.